In the near to moderate term, I really don't expect to see the
ability to have SLA's across arbitrary Internet connections. I do see
the ability for specific ISPs to offer SLA's on IP-based (i.e., not
necessarily public Internet) paths.
The reason for doing this is as much, or more for business as
technical reasons. Let's say ISP A, to whom you directly connect,
contracts with an enterprise for a particular SLA. ISP A has no
direct connectivity to the destination, which is served by ISP E.
Three ISPs, B, C, and D, interconnect the two endpoint AS.
OK. Assume ISP A sets a community or diffserv field that specifies
some sort of priority handling. Establishing internet-wide meanings
for such handling is NOT trivial. For sake of argument, you could
even say it uses RSVP, although RSVP is specifically designed for
intra-domain applications. However you do it, there is something
that identifies the traffic as preferred.
Perhaps ISP B has agreed with ISP A, as ISP B's upstream, to
recognize priority traffic. But why should ISPs C, D, and E honor a
demand for priority handling from other ISPs with which they have no
particular business relationship? ISP A is asking the others to use
additional resources for the priority traffic, but isn't compensating
the others to do so.
Aside from the technical and operational challenges, this simply
makes no business sense. What makes a good deal more business sense
is to think of the model used to provision Frame Relay.
Let's say you order a FR VC between New York and Los Angeles. You
order it from MCI. Assume that MCI does not have appropriate local
loops in NY and LA. The reality is that MCI will accept the order,
and then buy access service in NY from someone like Verizon and in LA
from someone like PacBell. The national part will run on MCI
facilities, unless MCI leases national capacity from a third party.
The point is that while the customer sees one bill, MCI has priced
that service to include access costs, and MCI will compensate all
other carriers involved. This gives everyone involved an economic
incentive to play nicely together.
Assuming the IP/MPLS/TE operational issues can be solved, it's not
unreasonable for an ISP to offer SLAs on VPNs for which it has
end-to-end responsibility. This is not the same thing as SLA across
the Internet, but the traffic may run over some of the other
facilities that contracted ISPs use to deliver public service.
>Suppose I need to do IPSec for whatever reason? I.e. I have data that MUST
>remain confidential, such as financial or medical information. ( I.e. GRE
>alone does cut it ) What does the configuration then look like?
>
>IPSec_router<>GRE_Router<>ISP<>GRE_Ruter<>Your_Company_MPLS<>GRE_Router<>ISP
><>GRE_Router<>IPSec_router
>
>Would that cover it?
>
>What are your engineers saying about latency in this kind of setup?
Nothing is free. If latency is a critical issue, you may have to
increase bandwidth on some of the links, not because you have enough
traffic to fill the link, but because faster media inherently have
less latency.
>I am not trying to knock you. I am just trying to get a good idea how this
>works. I have customers to whom this might be worth mentioning.
>
>Chuck
>
>
>Greetings,
>
>I am actually working with a company that will be offering a product with an
>SLA over the internet. One caveat is that you can not be more than one ISP
>away from the company on either end. They will be using GRE tunnels to the
>ingress router, then they will create MPLS Traffic Engineering Tunnels (TE)
>to transverse their network to the egress router and finally GRE tunnels to
>far end customers site. They have built a nationwide fiber optic network to
>support this product and it should be interesting to see if businesses
>choose to pay a premium for the SLA.
>
>Thanks,
>Jeff
___________________________________
UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html
FAQ, list archives, and subscription info: http://www.groupstudy.com
Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
